[to-be-updated] mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested.patch removed from -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The quilt patch titled
     Subject: mm: eliminate VMA_SPECIAL_FLAGS usage when hugetlb explicitly tested
has been removed from the -mm tree.  Its filename was
     mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Subject: mm: eliminate VMA_SPECIAL_FLAGS usage when hugetlb explicitly tested
Date: Sat, 03 Oct 2026 17:33:04 +0100

It is now an invariant that VMA_IO_BIT is not set by mm-managed mappings,
so each existing VMA_SPECIAL_FLAGS test need only test for
VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT and VMA_MIXEDMAP_BIT.

This is precisely a test for a fixed or non-mm-managed mapping.

Update a number of callsites which already explicitly handle hugetlb
mappings.

vma_supports_mlock() and ksm_compatible() also explicitly bail on droppable
mappings - excluding non-mm-managed, fixed or droppable mappings is exactly
what vma_is_mm_backed() tests for, so in these cases use this predicate.

should_skip_vma() tests for locked, fixed or non-mm-managed memory (having
already excluded hugetlb mappings) so simply test for those there.

No functional change intended.

Link: https://lore.kernel.org/20261003-b4-mmap-prepare-vma-flag-sanify-v4-33-a1f052500fd7@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: David Hildenbrand <david@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
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Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Kiryl Shutsemau <kas@kernel.org>
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---

 mm/internal.h |    4 +---
 mm/ksm.c      |    4 +---
 mm/vmscan.c   |    3 ++-
 3 files changed, 4 insertions(+), 7 deletions(-)

--- a/mm/internal.h~mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested
+++ a/mm/internal.h
@@ -1112,9 +1112,7 @@ static inline struct file *maybe_unlock_
 
 static inline bool vma_supports_mlock(const struct vm_area_struct *vma)
 {
-	if (vma_test_any_mask(vma, VMA_SPECIAL_FLAGS))
-		return false;
-	if (vma_test_single_mask(vma, VMA_DROPPABLE))
+	if (!vma_is_mm_backed(vma))
 		return false;
 	if (vma_is_dax(vma) || vma_is_hugetlb(vma))
 		return false;
--- a/mm/ksm.c~mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested
+++ a/mm/ksm.c
@@ -747,9 +747,7 @@ static bool ksm_compatible(const struct
 	if (vma_flags_test_any(&vma_flags, VMA_SHARED_BIT, VMA_MAYSHARE_BIT,
 			       VMA_HUGETLB_BIT))
 		return false;
-	if (vma_flags_test_single_mask(&vma_flags, VMA_DROPPABLE))
-		return false;
-	if (vma_flags_test_any_mask(&vma_flags, VMA_SPECIAL_FLAGS))
+	if (!vma_flags_is_mm_backed(&vma_flags))
 		return false;
 	if (file_is_dax(file))
 		return false;
--- a/mm/vmscan.c~mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested
+++ a/mm/vmscan.c
@@ -3521,7 +3521,8 @@ static int should_skip_vma(unsigned long
 	if (!vma_has_recency(vma))
 		return true;
 
-	if (vma->vm_flags & (VM_LOCKED | VM_SPECIAL))
+	if (vma_test(vma, VMA_LOCKED_BIT) || !vma_is_mm_managed(vma) ||
+	    vma_is_fixed_mapping(vma))
 		return true;
 
 	if (vma == get_gate_vma(vma->vm_mm))
_

Patches currently in -mm which might be from ljs@kernel.org are

mm-eliminate-vma_special_flags-check-in-lru_gen_look_around.patch
mm-avoid-use-of-vma_special_flags-in-migrate_vma_setup.patch
mm-eliminate-vm_special-vma_special_flags.patch
fuse-dax-do-not-set-vm_mixedmap.patch
mm-huge_memory-remove-vma_is_special_huge.patch
mm-vma-const-ify-vma_assert_stabilised-and-associated-functions.patch
mm-implement-and-use-vma_has_anon_rmap-silence-kcsan.patch
mm-update-comments-to-refer-to-anon-rmap-rather-than-anon_vma.patch
mm-vma-dont-remove-vma-from-rmap-if-pgoff-unchanged.patch